[PATCH v4 7/7] xen/arm: smmuv3: Add PCI devices support for SMMUv3

[Stewart Hildebrand <stewart.hildebrand@amd.com>]

From: Rahul Singh <rahul.singh@arm.com>

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
---
v3->v4:
* no change

v2->v3:
* rebase
* invoke iommu_add_pci_sideband_ids() from add_device hook

v1->v2:
* ignore add_device/assign_device/reassign_device calls for phantom functions
  (i.e. devfn != pdev->devfn)

downstream->v1:
* rebase
* move 2 replacements of s/dt_device_set_protected(dev_to_dt(dev))/device_set_protected(dev)/
  from this commit to ("xen/arm: Move is_protected flag to struct device")
  so as to not break ability to bisect
* adjust patch title (remove stray space)
* arm_smmu_(de)assign_dev: return error instead of crashing system
* remove arm_smmu_remove_device() stub
* update condition in arm_smmu_reassign_dev
* style fixup

(cherry picked from commit 7ed6c3ab250d899fe6e893a514278e406a2893e8 from
 the downstream branch poc/pci-passthrough from
 https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
---

This is a file imported from Linux with modifications for Xen. What should be
the coding style used for Xen modifications?
---
 xen/drivers/passthrough/arm/smmu-v3.c | 76 +++++++++++++++++++++++++--
 1 file changed, 72 insertions(+), 4 deletions(-)

diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index 8842db1ec07e..427946e68f9d 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -1469,14 +1469,32 @@ static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 }
 /* Forward declaration */
 static struct arm_smmu_device *arm_smmu_get_by_dev(const struct device *dev);
+static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
+			struct device *dev, u32 flag);
 
 static int arm_smmu_add_device(u8 devfn, struct device *dev)
 {
 	int i, ret;
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master *master;
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct iommu_fwspec *fwspec;
+
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+		int ret;
+
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		ret = iommu_add_pci_sideband_ids(pdev);
+		if ( ret < 0 )
+			iommu_fwspec_free(dev);
+	}
+#endif
 
+	fwspec = dev_iommu_fwspec_get(dev);
 	if (!fwspec)
 		return -ENODEV;
 
@@ -1533,6 +1551,17 @@ static int arm_smmu_add_device(u8 devfn, struct device *dev)
 	dev_info(dev, "Added master device (SMMUv3 %s StreamIds %u)\n",
 			dev_name(fwspec->iommu_dev), fwspec->num_ids);
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		ret = arm_smmu_assign_dev(pdev->domain, devfn, dev, 0);
+		if (ret)
+			goto err_free_master;
+	}
+#endif
+
 	return 0;
 
 err_free_master:
@@ -2622,6 +2651,27 @@ static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
 	struct arm_smmu_domain *smmu_domain;
 	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) && !is_hardware_domain(d) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		printk(XENLOG_INFO "Assigning device %04x:%02x:%02x.%u to dom%d\n",
+			pdev->seg, pdev->bus, PCI_SLOT(devfn),
+			PCI_FUNC(devfn), d->domain_id);
+
+		if ( devfn != pdev->devfn || pdev->domain == d )
+			return 0;
+
+		list_move(&pdev->domain_list, &d->pdev_list);
+		pdev->domain = d;
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+			return 0;
+	}
+#endif
+
 	spin_lock(&xen_domain->lock);
 
 	/*
@@ -2655,7 +2705,7 @@ out:
 	return ret;
 }
 
-static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+static int arm_smmu_deassign_dev(struct domain *d, uint8_t devfn, struct device *dev)
 {
 	struct iommu_domain *io_domain = arm_smmu_get_domain(d, dev);
 	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
@@ -2667,6 +2717,24 @@ static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
 		return -ESRCH;
 	}
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		printk(XENLOG_INFO "Deassigning device %04x:%02x:%02x.%u from dom%d\n",
+			pdev->seg, pdev->bus, PCI_SLOT(devfn),
+			PCI_FUNC(devfn), d->domain_id);
+
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+			return 0;
+	}
+#endif
+
 	spin_lock(&xen_domain->lock);
 
 	arm_smmu_detach_dev(master);
@@ -2686,13 +2754,13 @@ static int arm_smmu_reassign_dev(struct domain *s, struct domain *t,
 	int ret = 0;
 
 	/* Don't allow remapping on other domain than hwdom */
-	if ( t && !is_hardware_domain(t) )
+	if ( t && !is_hardware_domain(t) && (t != dom_io) )
 		return -EPERM;
 
 	if (t == s)
 		return 0;
 
-	ret = arm_smmu_deassign_dev(s, dev);
+	ret = arm_smmu_deassign_dev(s, devfn, dev);
 	if (ret)
 		return ret;
 
-- 
2.40.1